Treesearch

This session, attended by 90-100 people, focused on current wildlife management practices in the West, how they conflict with neotropical migratory bird conservation, and possible solutions for resolving these conflicts.

A recently-created complex of reserves spanning the Guatemala, Mexico, Belize borders in the southern Yucatan Peninsula constitutes 5.5 million acres of contiguous, protected lowland forest. Information is needed on compatibility of various land-uses and biodiversity protection in multiple-use zones of these reserves. To address these and other needs related to conservation of migrant songbirds, Peregrine Fund collaborators (6 Guatemalans and 5 North Americans) in 1992 began studies of songbirds wintering in and near the Guatemalan portion of the Maya/Calakmul/Rio Bravo reserve complex....

Under the National Forest Management Act of 1979, the USDA Forest Service is charged with maintaining viable populations of all existing native vertebrate species on lands they administer. Accomplishment of this responsibility requires complete assessment of all federally authorized, funded, or implemented projects that may jeopardize the continued existence of a species. An understanding of the processes of extinction and the characteristics of populations that make them more or less likely to persist is fundamental to such assessments. We review processes contributing to extinction and...

We studied habitat selection patterns of Merriam's Turkey (Meleagris gallopavo merriami) hens with poults in a ponderosa pine (Pinus ponderosa) ecosystem. Thirty-six radio-marked hens produced 19 broods, and we obtained 230 locations of hens with poults. We described vegetation of habitats using criteria from the Rocky Mountain Region, U.S. Forest Service, for determining effects of forest management and monitoring of wildlife populations. Most habitat units were 432 ha and corresponded to third-order habitats as described by Johnson (1980). Hens with poults selected large meadows and...

Populations of brood parasitic Brown-headed Cowbirds (Molofhrus afer) have increased to the point where they pose a potential threat to populations of many neotropical migrant songbirds. Because cowbirds mostly feed in short grass (e.g., pastures and lawns) or on bare ground (e.g., row crops), they benefit directly from human activities. Cowbirds commute up to 7 km between feeding areas and habitats where they search for host nests, often favoring forest edge or secondary growth. Several neotropical migrants with restricted geographical ranges are endangered, at least partly as a result of...

Four case studies were presented to demonstrate how neotropical migrant bird conservation is being integrated info other resource management activities in the Midwest.

Avian communities that are associated with forest habitat attributes are affected by silvicultural and other stand influences. Some species have specific habitat requirements, whereas others occupy a broad range of vegetative conditions. In general, bird species richness and density are positively related to stand foliage volume and diversity. Bird density and diversity are usually high in young brushy stands, decrease in dense pole stands as canopies close and shade out understories, and are highest in older stands with diverse foliage strata. Tree harvesting generally favors early...

Douglas-fir beetle (Dendroctonus pseudotsugae Hopk.) occurs throughout the range of its principal host, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). At epidemic levels, the beetle causes considerable mortality in large-diameter Douglas-fir trees. Wind storms, drought, fire, and other factors have been reported as precedent conditions for epidemics of Douglas-fir beetle. An impact model has been developed to simulate tree mortality during such epidemics. The model has been linked to the Stand Prognosis Model (Forest Vegetation Simulator). This is a guide for using the model.

We briefly review the effects of climate (particularly drought and hurricanes), insect outbreaks, and fire on populations of migrant birds. An important feature of all of these natural disturbances is that they occur over a variety of spatial and temporal scales, thus precluding any simple generalization of their effects or of methods for mitigating those effects. We recognize that (1) natural catastrophic phenomena will inevitably occur; (2) an ecosystem will consist of a mosaic of patches that reflects the recurrence time and spatial extent of these disturbances; and (3) after some...

The Southeast Management Working Group for Partners in Flight initiated a prioritization scheme in April 1991 to help guide regional and local conservation efforts for Neotropical migratory landbirds. Preliminary breeding season priorities have been established in each of 24 physiographic areas for species and habitats, with some non-breeding season priorities set as well. Interested parties have met in most physiographic areas in the Southeast to review preliminary priorities and organize for future action. Species of regional concern, habitats of regional and physiographic area concern,...